Honestly, I wouldn't pay much at all for someone to write my resume for me, because Microsoft Word offers the very same thing (in a Wizard/Tutorial) - for free. You can find tips online for how to write it for free, too. And I've had a lot of experience over the years in writing resumes that sound professional and convincing, so it's not a service that I would pay for at all. But if I did, probably not much to be honest with you. $5, maybe?
Something else that might come in handy is, you know all of those job listing sites? Like "Yahoo Hot Jobs", Snag-a-Job, and so on? I always find them so incredibly hard to navigate to be honest with you. It's always so hard to find job types that would actually interest me. Maybe as a service, you could think about asking them for information on what they're looking for in a job, and where their location is - and you could come up with a more personalized list of places that are hiring in their area? I'm not sure what you'd call that, but it's an idea anyway.